Gliederung

The alkaloid nicotine is the addictive component of tobacco smoke. The aim of this study is the investigation of the possible alteration of the carcinogenic potential of nicotine as a result of pH-conditions being found in the human aerodigestive tract with reflux of gastric acid.

Enzymatically isolated human cells of the Tonsilla palatina were incubated for 1 hour with pH-values from 4.3, 4.7, 5, 5.5, 6, 7, 7.5 up to 8.3 both without and with 16 mM nicotine. Cytotoxic effects were quantified with the help of the trypan blue exclusion test. DNA-migration due to single strand breaks, alkali labile and incomplete excision repair sites were demonstrated with the single-cell microgel electrophoresis (Comet) assay.

Lymphatic tissue of the palatine tonsils showed pH-dependency of DNA-migration. A lower medium pH-value led to a higher DNA-migration distance in the electric field. A concomitant exposure to nicotine showed more pronounced effects with low pH-values.

In conclusion, enforced mutagenic effects of this alkaloid combined with acidic pH-conditions may focus on a possible mechanism of cancer induction in reflux patients.